So, if you're unaware, the basic math of PF2e's armour items assumes that for light and medium armour, (item bonus + dex cap) = 5, and for heavy armour, = 6. This means that as long as you can pick an armour that has a lower dex cap than your dex bonus, you are expected to be getting either 5 or 6 AC from your armour.
With all that said, there are a ton of armours out there that offer some kind of tradeoff, where that formula doesn't hold. For example, the Armoured Coat gives +4 AC between item bonus and dex cap, but it has the flexible trait which negates the check penalty to athletics and acrobatics checks. In my mind, that's a crazy tradeoff to make. The extra AC is so much more important.
At the end of the day though, I don't have the time to analyze the tradeoff offered by all of these "sub-optimal" armours. So yeah, I'd love to hear if anyone has experience with an armour item that yields less than 5 AC (or 6 for heavy armour) and yet the tradeoff was actually worth it for them.